Ice protection system and controller

Abstract

An ice protection system and method capable of anti-icing and de-icing aerodynamic structures and surfaces is provided comprising a Resistive Heat Coat (RHC) controller and a heating device. The RHC controller comprises a RHC power circuit topology having a processor and a buck converter. The RHC controller further comprises a RHC control algorithm. The heating device comprises a plurality of resistive heating elements, such as CNT-based resistive heaters. The ice protection systems and methods disclosed can achieve an efficiency of 98% or greater while employing a direct current (DC) power supply and “hard switching” with a switching frequency of at least 500 kHz.

What is claimed is: 
     
       1. An ice protection system connected to an associated aerodynamic structure, the system comprising:
 a heating device having a plurality of carbon nanotube (CNT) resistive heating elements; and 
 a controller comprising:
 a power circuit topology having at least one buck converter; and 
 a processor in communication with memory, the memory storing instructions which are executed by the processor causing the processor to:
 determine an ideal setpoint temperature for one or more of the plurality of CNT resistive heating elements; 
 determine a progressively adjusted setpoint temperature by comparing the ideal setpoint temperature to a current measured temperature for one or more of the plurality of CNT resistive heating elements; and 
 produce a proportional drive signal output based on at least the measured current temperature and the instantaneous progressively adjusted setpoint temperature. 
 
 
 
     
     
       2. The system of  claim 1 , wherein a heater drive power comprises a direct current (DC) power supply connected to the heating device. 
     
     
       3. The system of  claim 1 , wherein the buck converter comprises one or more switching field-effect transistors (FETs) formed from silicon carbide (SiC). 
     
     
       4. The system of  claim 1 , wherein the power circuit topology has a switching frequency of 500 kHz or greater. 
     
     
       5. The system of  claim 1 , wherein the power circuit topology has a transition time between on and off states of less than 10 nanoseconds. 
     
     
       6. The system of  claim 1 , wherein the power circuit topology has an efficiency rating of greater than 98% at rated output. 
     
     
       7. A method of powering an ice-protection system of an associated aerodynamic structure wherein the ice-protection system has a controller and a heating device, the method comprising:
 sampling the temperature of at least one heating channel of the heating device; 
 determining an ideal setpoint temperature for the at least one heating channel of the heating device; 
 determining a progressively adjusted setpoint temperature for the at least one heating channel; 
 generating a proportional drive signal for the at least one heating channel of the heating device; 
 converting the proportional drive signal for the at least one heating channel of the heating device into a power output to be delivered to at least one heating channel; and 
 delivering the power output to the at least one heating channel; 
 wherein one or more of sampling the temperature, determining an ideal setpoint temperature, determining a progressively adjusted setpoint temperature, generating a proportional drive signal, converting the proportional drive signal, and delivering the power output is performed by the controller of the ice-protection system. 
 
     
     
       8. The method of  claim 7 , wherein the ideal setpoint temperature for the at least one heating channel is determined about once per second. 
     
     
       9. The method of  claim 7 , wherein the sampling of the temperature of at least one heating channel is performed using two channel thermocouples per heating channel. 
     
     
       10. The method of  claim 9 , wherein the temperature of at least one heating channel is sampled at least 125 times per second. 
     
     
       11. The method of  claim 9 , wherein the method further comprises determining a conditioned temperature for at least one heating channel based on more than one sampled temperature of the at least one heating channel, and at least one of the determining the ideal setpoint temperature, the determining an progressively adjusted setpoint temperature, and the generating the proportional drive signal is further based on the conditioned temperature for the at least one heating channel. 
     
     
       12. The method of  claim 11 , wherein the conditioned temperature for at least one heating channel is updated at least every 25 milliseconds. 
     
     
       13. The method of  claim 7 , wherein the converting the proportional drive signal includes:
 calculating a duty cycle for a buck converter of the controller associated with at least one heating channel based on the proportional drive signal; and 
 determining the power output to be delivered to the at least one heating channel based on the duty cycle. 
 
     
     
       14. The method of  claim 7 , wherein the power output is delivered to at least one heating channel from a direct current (DC) power supply of the controller. 
     
     
       15. The method of  claim 7 , wherein the power from the controller is routed to at least one heating channel through a demultiplexer module. 
     
     
       16. The method of  claim 7 , wherein the heating device is an array of CNT resistive heating elements and at least one heating channel is a group of one or more CNT resistive heating elements of the array of CNT resistive heating elements. 
     
     
       17. A method of powering an ice-protection system of an associated aerodynamic structure wherein the ice-protection system has a controller and a heating device, the method comprising:
 receiving system input data for the associated aerodynamic structure; 
 evaluating the system input data for the associated aerodynamic structure to determine a mode of operation for the ice-protection system; 
 sampling the temperature of at least one heating channel of the heating device; 
 determining an ideal setpoint temperature for the at least one heating channel of the heating device based on the mode of operation for the ice-protection system, the system input data for the associated aerodynamic structure, and the temperature of the at least one heating channel; 
 determining a progressively adjusted setpoint temperature for the at least one heating channel based on the mode of operation for the ice-protection system, the system input data for the associated aerodynamic structure, the temperature of the at least one heating channel, the ideal setpoint temperature for the at least one heating channel, and a configuration setting data for the heating device; 
 generating a proportional drive signal for the at least one heating channel of the heating device using a proportional-integral-derivative control loop based on the temperature of the at least one heating channel, the system input data for the associated aerodynamic structure, and the instantaneous progressively adjusted setpoint temperature for the at least one heating channel; 
 converting the proportional drive signal for the at least one heating channel of the heating device into a power output to be delivered to at least one heating channel; and 
 delivering the power output to the at least one heating channel; 
 wherein one or more of the receiving system input data, sampling the temperature, evaluating the system input data, determining an ideal setpoint temperature, determining a progressively adjusted setpoint temperature, generating a proportional drive signal, converting the proportional drive signal, and delivering the power output is performed by the controller of the ice-protection system. 
 
     
     
       18. The method of  claim 17 , wherein the progressively adjusted setpoint temperature for the at least one heating channel is determined by adjusting the temperature of the at least one heating channel by matching to a halfwave of a sinusoid, and wherein the amplitude and period of the sinusoid is based on the mode of operation for the ice-protection system, the system input data for the associated aerodynamic structure, the temperature of the at least one heating channel, the ideal setpoint temperature for the at least one heating channel, and a configuration setting data for the heating device. 
     
     
       19. The method of  claim 17 , wherein a phase of flight state is determined for the associated aerodynamic structure based on the system input data received. 
     
     
       20. The method of  claim 19 , wherein the ideal setpoint temperature for the at least one heating channel is further based on the phase of flight state.